JPH10106593A - Solid high molecular fuel cell, operating method thereof, and solid high molecular fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the control of moisturizing temperature by specifying thickness of an electrolyte film of a solid high molecular type fuel cell. SOLUTION: An electrolyte membrane 11 is a rectangular ion exchange membrane, in which the reinforcing agent having sulfuric group is blended, is provided with four circular through holes, which form an inner manifold for supplying and discharging reacting gas, at four corners of a peripheral part thereof. A through hole, which forms an inner manifold for supplying and discharging cooling water, is provided at a central part of the peripheral part. Thickness of the electrolyte membrane 11 is set at 3-40 micron, desirably, at 5-40 micron, because in the case where the membrane thickness exceeds 40 micron, dependency if unit cell voltage in relation to the moisturizing temperature increases, and lowering of unit cell voltage due to the lowering of moisturizing temperature increases, and in the case where membrane thickness is less than 3 micron, the electrolyte membrane 11 is hard to be handled at the time of assembling a battery, and in the case where membrane thickness is less than 5 micron, gas cross leak increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte fuel cell, and more particularly to an improvement in a technique for wetting a polymer membrane during cell operation.

[0002]

2. Description of the Related Art A polymer electrolyte fuel cell has a cell in which a cathode is arranged on one side of an electrolyte membrane composed of a polymer electrolyte membrane and an anode is arranged on the other side, and ribs and gas channels are formed. It has a configuration in which a plurality of separator plates are alternately stacked. Then, a cathode gas (an oxidizing gas such as air) is supplied to a cathode, and an anode gas (a hydrogen-rich fuel gas) is supplied to an anode, and power is generated by causing an electrochemical reaction between the two gases. In this electrochemical reaction, hydrogen in the anode gas is converted into hydrogen ions, and the inside of the electrolyte membrane moves from the anode side to the cathode side. As the conductivity of the hydrogen ions increases, the output voltage per unit cell increases. Can be increased. Therefore, when selecting the material and film thickness of the electrolyte membrane, this ion conductivity is taken into consideration, and the load during cell lamination, the pressure difference of the reaction gas, or the physical and chemical Conventionally, in consideration of preventing mechanical damage, an ion exchange membrane having a film thickness of about 100 μm made of a material having a strong cation exchange group such as Nafion (trade name of DuPont, USA) is conventionally used. Was mainly adopted.

In such a polymer electrolyte fuel cell, when the electrolyte membrane is dried, the ionic conductivity is reduced. Therefore, during operation, the anode gas or the cathode gas is heated at the operating temperature (cell temperature) so as to keep the electrolyte membrane wet. Usually 50 ° C ~ 8
The method mainly employs a method of humidifying so as to have a dew point at 0 ° C. (for example, humidifying by bubbling an anode gas or a cathode gas into hot water around an operating temperature of about 80 ° C.) and supplying the fuel gas to a fuel cell. Was.

However, in the above humidification method, a heater or the like and an auxiliary power device for the heater and the like are separately required in order to obtain hot water, so that the efficiency of the system is inferior to that extent. On the other hand, Japanese Patent Application Laid-Open No. 7-326376 discloses that a heat medium such as water or water vapor is circulated between the fuel cell and each of the reaction gas humidifiers, thereby generating the fuel cell with power generation. A technique is disclosed in which heat can be used to humidify each reaction gas. With this technique, it is possible to eliminate the need for a heater power or the like that has conventionally been required as a heat source for humidification.

[0005]

However, in such a conventional polymer electrolyte fuel cell, if the humidification temperature is not strictly controlled in a narrow range near the operating temperature of the battery, the moisture retention of the electrolyte membrane cannot be maintained. There was a problem that it would be sufficient or excessive. In addition, since the electrochemical reaction of power generation by the fuel cell is an exothermic reaction, it is necessary to forcibly cool the fuel cell during operation, and therefore, a cooling water tank must be provided in addition to the humidifier. There was a problem regarding the simplicity of the system configuration.

The present invention has been made in view of the above problems, and it is a first object of the present invention to provide a polymer electrolyte fuel cell in which the humidification temperature can be easily controlled and a method of operating the same. A second object is to provide a polymer electrolyte fuel cell system having a simple system configuration.

[0007]

In order to achieve the first object, the present invention provides a cell in which an anode and a cathode are arranged via an electrolyte membrane, a holding member for holding the cell,
An anode gas channel is provided between the sandwiching member and the anode, and a cathode gas channel is provided between the separator plate and the cathode in close contact with the anode or the cathode, respectively. The thickness of the electrolyte membrane is 3 to 40 μm.

[0008] By reducing the thickness of the electrolyte membrane in this manner, it is possible to generate power even using a reaction gas having a dew point lower than the operating temperature of the battery. Control becomes easy. In such a polymer electrolyte fuel cell, if the humidifying means is brought into contact with water at room temperature and humidified and supplied to the fuel cell, the wet state of the electrolyte membrane can be maintained. In this case, a heat source for generating hot water for humidification is not required separately,
The system configuration can be simplified.

The polymer electrolyte fuel cell further comprises a product water recovery means for recovering water generated by the cell reaction, and humidifying at least one of the anode gas and the cathode gas using the water recovered by the recovery means. If humidifying means is provided, there is no need to separately supply humidifying water from the outside. If the operating temperature of the battery is equivalent to room temperature, both the anode gas and the cathode gas can be operated without humidification.

This can be said to be very effective when simplicity is required, for example, in a portable fuel cell power generation system. Further, in order to achieve the second object, the polymer electrolyte fuel cell system of the present invention comprises a cell in which an anode and a cathode are disposed via an electrolyte membrane, and separator plates, which are alternately stacked, A gas channel is formed between the anode and the cathode, and a cooling water flow passage is opened, and cooling water is circulated and supplied to the cooling water flow passage from a water storage unit provided outside the polymer electrolyte fuel cell. And a humidifying unit for introducing and / or humidifying at least one of an anode gas and a cathode gas into the water storage unit.

In the above polymer electrolyte fuel cell system,
The water in the water storage unit serves both for cooling and for humidifying the reaction gas. Since the heat generated by the power generation of the battery is used for humidifying the reaction gas, it is not necessary to separately provide a heat source such as a heater for obtaining hot water, so that the system configuration can be simplified accordingly. In such a polymer electrolyte fuel cell system, if the product water recovery means for recovering the water generated by the cell reaction and sending it to the water storage unit is provided, the water lost from the water storage unit due to the humidification can be obtained. Need not be replenished separately from the outside.

Further, if the system is provided with a reformer that generates steam using the water in the water storage unit and generates a hydrogen-rich gas by steam reforming the fuel gas, the water in the water storage unit can be used. Since it is used for steam reforming, a simple system configuration can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 is an exploded perspective view showing the structure of a basic unit 1a of a polymer electrolyte fuel cell (hereinafter simply referred to as fuel cell 1). Basic unit 10 of this fuel cell 1
Reference numeral 0 denotes a cell 10 in which an anode 12 and a cathode 13 (not visible in FIG. 1 on the back of the electrolyte membrane 11; see FIG. 2) are disposed in the center of the electrolyte membrane 11;
And a pair of separator plates 20 and 30 sandwiching the anode plate 12 and the anode plate 12 and the cathode plate 13.
A pair of current collectors 4 interposed between 0, 30 and cell 10
0, 41, the outer peripheral portions of the separator plates 20, 30 and the cell 1
Sealing material 5 for sealing this portion inserted between
0, 60 are stacked.

The fuel cell 1 is provided with a cooling plate 11 every five such basic units 100 are stacked.
0 is inserted to form a laminate, and both ends of the laminate are pressed by a pair of end plates (not shown).
Note that the number of basic units to be stacked is set according to the voltage to be output. The electrolyte membrane 11 is a rectangular ion exchange membrane. Four circular through holes 14, 15, 16 for forming internal manifolds for supplying and discharging the reaction gas are formed at four corners of the periphery. , 17 (not visible in FIG. 1).

Further, through holes 18, 19 (19) for forming an internal manifold for supplying and discharging cooling water are formed in the center of the peripheral portion.
Are not visible in FIG. ) Has been established. The thickness of the electrolyte membrane 11 is 3 to 40 μm, preferably 5 to 40 μm.
It is set in the range of μm. The reason is that if the thickness exceeds 40 μm, the dependence of the single cell voltage on the humidification temperature increases, and the single cell voltage decreases due to the decrease in the humidification temperature. This is because it becomes difficult, and when it is less than 5 μm, gas cross leak increases.

As described above, the electrolyte membrane 11 is not only made thinner than the conventional one, but is also made of a material containing a reinforcing agent having no ion exchange group in order to secure the strength of the membrane. And Specific examples of the electrolyte membrane 11 include a mixed membrane obtained by mixing a polystyrene resin having a sulfonic acid group or perfluorocarbon sulfonic acid with polytetrafluoroethylene (Teflon, manufactured by DuPont) as a reinforcing agent, a fluorocarbon sulfonic acid and a reinforcing agent Cation-exchange polymer membranes such as a mixed membrane with polyvinylidene fluoride as above, and further grafted with such a mixed membrane with trifluoroethylene as a reinforcing agent. These polymer membranes are formed to a predetermined thickness by pressing a mixture of a cation exchange resin and a reinforcing agent.

Since the electrolyte membrane 11 contains a reinforcing agent having no ion exchange group as described above, the electrolyte membrane 11 has a higher ion conductivity than a membrane made of only an ion exchange resin (Nafion manufactured by DuPont). Drops. Although this point is negative for the power generation of the cell, the thinner the film thickness, the lower the internal resistance, which contributes to the power generation of the cell. Therefore, it is possible to obtain the same or higher cell power as compared with the conventional case of using an electrolyte membrane of about 100 μm made of a single ion-exchange resin alone.

The anode 12 and the cathode 13 are both formed bodies of a predetermined thickness (20 to 30 μm) of the same size and made of platinum-supporting carbon, and are adhered to the center of the electrolyte membrane 11. Loading amount (0.7 mg / cm
Adjusted to 2). Each of the separator plates 20 and 30 is a plate made of a carbon material having the same size as the electrolyte membrane 11, and has a plurality of anode gas channels 2 on the side of the separator plate 20 facing the anode 12.
.. Are not visible because they are formed on the back side of the separator plate 20 in FIG. 1 (see FIG. 2), and a plurality of cathode gas channels 31 are provided on the side of the separator plate 30 facing the cathode 13. … Is engraved.

Each of the separator plates 20, 30 has a circular through hole 24, 25, 26,
27 and through holes 34, 35, 36, 37 (37 is not visible in FIG. 1), and through holes 38, 39 (39 are not visible in FIG. 1) at the center of the periphery. Have been. As shown in FIG.
6 are connected to the plurality of cathode gas channels 31..., While not shown in FIG. 1, similarly, the through holes 25 and 27 are connected to the plurality of cathode gas channels 21.

The current collectors 40 and 41 are formed of a porous carbon thin plate subjected to a water-repellent treatment, and have dimensions slightly larger than those of the anode 12 and the cathode 13. And
The anode 12 and the plurality of anode gas channels 21 are opposed to each other via the current collector, and the cathode 1 is connected via the current collector 41.
3 and the plurality of cathode gas channels 31 are opposed to each other.

The sealing members 50 and 60 are frame-shaped plates made of a resilient material (for example, EPDM rubber), the outer periphery of which is the same size as the outer periphery of the electrolyte membrane 11, and the inner periphery thereof. 50a and 60a are the outer periphery 1 of the anode 12.
2a, outer periphery 13a of cathode 13 (not visible in FIG. 1).
The dimensions are the same as the outer circumferences 40a and 41a of the current collectors 40 and 41.

Each of the sealing members 50 and 60 also has six circular through holes 54 to 59 (57) at positions corresponding to the through holes 24 to 29 of the separator plates 20 and 30, respectively.
And 59 are not visible in FIG. ) And 64-69 (6
7 and 69 are not visible in FIG. ) Has been established.
The cooling plate 110 is a thin plate having the same vertical and horizontal dimensions as the electrolyte membrane 11, and is formed such that a plurality of cooling water passages 111 face the separator 30 (see FIG. 2).

The cooling plate 110 also has six through holes 114 to 119 at positions corresponding to the through holes 24 to 29 of the separator plates 20 and 30.
The through holes 118 and 119 communicate with the cooling water passage 111. By laminating the above members, namely, the cell 10, the separator plates 20, 30, the sealing material 5
By stacking the cooling plates 110, 0 and 60, a manifold for supplying the cathode gas is constituted by the through holes 24, 54, 14, 64, 34, 114, and the through holes 26, 56, 16, 66, 36, A manifold for discharging the cathode gas is constituted by 116. The through holes 25, 55, 15, 65, 35, and 115 constitute a manifold for supplying anode gas, and the through holes 27... Constitute a manifold for discharging anode gas.

The through holes 28, 58, 18, 68, 3
A cooling water supply manifold is constituted by 8, 118, and a cooling water discharge manifold is constituted by through holes 29, 19, 69, 39, 119. Then, the cathode gas supplied to the cathode gas supply manifold is distributed to the plurality of cathode gas channels 31,
After being used for power generation at the cathode 13, it is discharged from a cathode gas discharge manifold. On the other hand, the anode gas supplied to the anode gas supply manifold is distributed to the plurality of anode gas channels 21 and used by the anode 12 for power generation, and then discharged from the anode gas discharge manifold. ing.

The cooling water supplied to the cooling water supply manifold is distributed to a plurality of passages 111, used for cooling, and then discharged from the cooling water discharge manifold. FIG. 2 (FIG. 2 is a cross-sectional view of the fuel cell 1 shown in FIG.
It is sectional drawing in an X-axis. ), The electrolyte membrane 11
Is sandwiched between separator plates 20 and 30 via sealing materials 50 and 60.

The current collector 40 includes an inner periphery 50 a of the sealing material 50.
, And the current collector 41 has just fit inside the inner periphery 60 a of the sealing material 60. [Humidifying Means] In the fuel cell 1 having the above-described structure, humidification of the reaction gas is performed by bringing the reaction gas into contact with water at room temperature, that is, water that is not heated. Specifically, as is conventionally known, a reaction gas is bubbled into water, water is sprayed into the reaction gas, or an ultrasonic vibrator is provided at the bottom of the water layer to form a reaction gas passing therethrough. It can also be performed using a humidifier that disperses fine particles of water,
As a simpler method, it can be performed using the following humidifier.

As shown in FIG. 3, an upper cover 101a which can be opened and closed.
And a water retaining portion 101 composed of a main body 101b is inserted into a pipe 102 for supplying a reactive gas. And
Pure water 103 is stored in the main body 101b, and a water layer is formed. The internal structure is such that the reaction gas passes over the aqueous layer (thick arrow in the figure). Retention part 101
The upper lid 101a and the main body 1
01b and a main body 101b
And the upper lid 101a are fastened.

As a result, the reaction gas is almost saturated with water vapor (dashed arrow in the figure) generated from the aqueous layer at room temperature, and becomes a dew point gas equivalent to room temperature. Such a humidifier can be provided in only one of the anode gas supply pipe and the cathode gas supply pipe to operate the fuel cell, but can also be provided in both pipes.

As described above, in the fuel cell 1, there is no need for a heat source for generating hot water for humidification, an auxiliary power unit as a power source for the humidification, or a mechanism for controlling the water temperature. The operation can be performed by humidifying the reaction gas alone, because the thickness of the electrolyte membrane is made thinner than before as described above. In addition, it can also be used for humidification of the reaction gas using the water generated by the cell reaction of the fuel cell 1 as follows.

That is, the gas flowing out from at least one of the respective reaction gas discharge manifolds is led to a gas-liquid separator (not shown), and the water recovered therefrom is passed through a pipe 10.
4 and introduced into the main body 101b,
There is no need to externally supply water to the main body 101b. Further, since the generated water has been heated to a temperature close to the operating temperature, the humidification of the reaction gas in the water retaining section 101 proceeds more.

Further, an ultrasonic vibrator (not shown) may be provided at the bottom of the water layer of the stagnation portion 101 to scatter water fine particles in the passing reaction gas, thereby humidifying the reaction gas. it can. In addition, since the fuel cell 1 has a thinner electrolyte membrane than before, when operating at a temperature equivalent to room temperature, it is possible to generate power without humidifying both the anode gas and the cathode gas (see Experiment 2). It can be said that such an operation mode is very effective when, for example, simplicity of a portable fuel cell power generation system is required.

[Consideration on Moisturizing Electrolyte Membrane]
Moisturizing of the electrolyte membrane 11 during power generation will be described from the viewpoint of the partial pressure of water vapor. During power generation, the electrolyte membrane comes into contact with water vapor flowing through the opposed anode and cathode using the reaction gas as a medium. At this time, at the operating temperature, the water vapor partial pressure of the humidified anode gas flowing through the anode gas channel and the water vapor partial pressure of the humidified cathode gas flowing through the cathode gas channel are formed between the resin fibers that are the material of the electrolyte membrane. If the equilibrium with each of the water vapor partial pressures of the minute gaps (hereinafter referred to as an electrolyte membrane space) is ensured, evaporation of the water adsorbed on the electrolyte membrane can be prevented.

On the other hand, when the water vapor partial pressure of the anode gas is smaller than the water vapor partial pressure of the electrolyte membrane space, the adsorbed water of the electrolyte membrane is turned into steam on the anode side, and the water vapor partial pressure of the cathode gas becomes the water vapor partial pressure of the electrolyte membrane space. If smaller, the adsorbed water of the membrane is similarly vaporized to the cathode side. The water lost by vaporization is replenished by the water generated by the oxidation reaction at the cathode. However, when the thickness of the electrolyte membrane is large, it cannot be supplied to the inside of the membrane or the anode side. In the wet state in the thickness direction.

On the other hand, if the thickness of the electrolyte membrane is small, the amount of water lost by the water produced by the oxidation reaction at the cathode should be sufficiently compensated not only on the membrane surface but also inside the membrane. Since no gradient occurs in the wet state in the thickness direction of the membrane, a decrease in the ion conductivity of the membrane can be suppressed. The effect as described above can be said to be more remarkable as the film thickness is smaller.

[Experiment 1] ★ Method of Experiment The following experiment was conducted using the same fuel cell 1 as described above, except that the thickness of the electrolyte membrane was changed to 125 μm, 40 μm, and 20 μm. . The electrolyte membrane is made of a perfluorosulfonic acid resin as a main material and manufactured using Teflon as a reinforcing agent. (In Experiments 2 and 3, membranes made of the same material are used.) ).

Current density 500 mA / cm ² , operating temperature 8
Cell 1 when operating under the operating conditions of 0 ° C. and humidifying temperature of anode gas of 80 ° C. and changing the humidifying temperature of cathode gas
Voltage per unit (mV) and internal resistance (mΩ · cm ² )
Was measured. The results are shown in FIGS. Note that air was used as a cathode gas, and hydrogen gas was used as an anode gas.

The humidification of each reaction gas is performed by bubbling each reaction gas in water having a predetermined water temperature, and the water temperature becomes the humidification temperature. Then, the amount of water vapor generated at the temperature is contained in the cathode gas, that is, the bubbled cathode gas contains water vapor whose dew point is the water temperature. In addition, it measured also about the case of non-humidification of a cathode gas.

★ Results and Discussion of Experiment First, as shown in FIG.
At ℃, the voltage shows almost the same maximum value irrespective of the film thickness, and the voltage shows a tendency to decrease as the humidification temperature of the cathode gas decreases, but as the electrolyte membrane becomes thinner, the voltage becomes smaller. , The temperature dependence of the voltage decreases, and the rate of decrease in voltage due to a decrease in the humidification temperature decreases. Therefore, a high voltage can be obtained at a low cathode gas humidification temperature. That is, since the temperature range of the humidification control is expanded, it can be said that the humidification can be easily controlled.

For example, when a conventional electrolyte membrane having a thickness of 125 μm is used, if a voltage of 480 mV is to be obtained,
Must be humidified at a temperature of at least 60 ° C,
If an electrolyte membrane having a thickness of about 40 μm, which is about one third of the conventional thickness, is used, even if the humidification temperature is greatly reduced to 45 ° C., it is sufficient to use 480.
mV can be generated. 20 μm thinner film thickness
In this case, 480 mV can be secured even if the cathode gas is supplied without humidification without humidification.

When the humidification temperature exceeds 80 ° C. for all the film thicknesses, the voltage drops because the operating temperature of the battery is 8 ° C.
Since the temperature is 0 ° C., the water vapor in the cathode gas becomes supersaturated, dew forms on the electrode surface, and the permeability of the cathode gas into the electrode is impaired, so that a sufficient oxidation reaction at the cathode cannot be performed. In this experiment, 20, 40, 1
The film thickness of 25 μm was examined, and it was confirmed by a separate experiment that the temperature dependency of the voltage tended to increase as the film thickness increased.

FIG. 5 shows that the smaller the film thickness, the smaller the internal resistance. For example, at a cathode gas humidification temperature of 50 ° C., if the film thickness is 125 μm, the electrolyte membrane cannot sufficiently secure the wet state, so that the internal resistance of the single cell shows a very large value of 450 mΩ · cm ^2. At 40 μm, it is reduced to 250 mΩ · cm ^2, and when the film thickness is 20 μm, it is reduced to 150 mΩ · cm ² and one third of 125 μm. In addition, the film thickness of 40 μm and 20
Even when the cell having a thickness of 125 μm was operated without humidification, the internal resistance was smaller than that obtained when the humidification temperature of the cathode gas having a thickness of 125 μm was 50 ° C.

In the above experiment, the anode gas was 8
Although the case where humidification was performed at 0 ° C. was examined, the voltage per single cell was slightly reduced even when only the anode gas and the cathode gas were not humidified at the same time and only one of them was humidified. Almost the same tendency was observed. [Experiment 2] ★ Experimental method Using the fuel cell 1 having a film thickness of 20 μm used in Experiment 1, the operation temperature was set to room temperature (25 ° C.), and the anode gas and the cathode gas were operated without humidification. Therefore, the current density is set to 0
The cell voltage (mV) was measured while changing in the range of ５００500 mA / cm ² .

★ Results of Experiment FIG. 6 is a characteristic diagram showing the results of the above experiment, showing the relationship between current density and cell voltage. According to FIG. 6, the current density is 40
It can be seen that a cell voltage of 480 mV or more can be obtained in a range of 0 mV / cm ² or less.

[Experiment 3] ★ Experimental Method As shown in FIG. 7, an electrolyte membrane having a film thickness of 1 to 125 μm was
Hydrogen gas flowing through the electrolyte membrane into the nitrogen gas through the electrolyte membrane, sandwiching the periphery of the front and back surfaces with an airtight housing, and enclosing hydrogen gas and nitrogen gas in a state facing the space formed by the housing and the membrane. Was measured as the amount of cross leak.

★ Experimental Results FIG. 8 shows relative values when the cross leak amount for each film thickness is 125 μm and the cross leak amount is 1 for each film thickness. As shown in FIG. 8, the cross leak amount tended to increase as the thickness of the electrolyte membrane became thinner. And 5μm
It can be seen that when the value is less than the above, the amount of cross leak increases remarkably. Therefore, it can be said that the film thickness is preferably 5 μm or more.

[Embodiment 2] In the polymer electrolyte fuel cell system according to the present embodiment, the electrolyte membrane 11 has a thickness of 12
A polymer electrolyte fuel cell having the same configuration as that of the fuel cell 1 except that a 5 μm membrane of perfluorocarbon sulfonic acid resin (Nafion manufactured by DuPont) is used, a humidifying device 70 described below, and a piping system connecting them. The humidifier 70 humidifies only the anode gas during battery operation.

Hereinafter, the humidifying device 70 will be described with reference to FIGS.
The configuration and the humidification method will be described. FIG. 9 is an external view of the humidifier 70, and FIG. 10 is a schematic sectional view of the humidifier 70. As shown in FIG. 9, the humidifying device 70 includes a bottomed cylindrical tubular device main body 70a and a top plate 70b, and upper and lower side surfaces of the main body 70a are connected with piping 701 and 702 for supplying and discharging anode gas. ing.

Further, the humidifying device 70 also serves as a cooling water tank for cooling the fuel cell, and a pipe 703 for supplying cooling water to the fuel cell is provided in the humidifying device 70.
A pipe 704 for introducing cooling water into the apparatus main body is connected to the top plate 70b at the lower part of the side surface a. As shown in FIG. 10, the internal space 710 of the humidifying device 70 is partitioned by a heat conductive partition plate 73, and an anode gas humidifying tank 71 and a cooling water tank 72 are formed, and pure water is stored inside. Heat is exchanged between the two tanks via the partition plate 73.

In the anode gas humidifying tank 71, the above-mentioned anode gas supply pipe 701 is inserted into the water layer at its tip, and the above-mentioned anode gas discharge pipe 702 is inserted.
Is communicated with the tank 71 at a position above the water layer.
The cooling water pipes 703 and 704 communicate with the cooling water tank 72.

A SUS foam filter 74 is provided below the partition plate 73, for example. As a result, water can flow between the anode gas humidifying tank 71 and the cooling water tank 72, and bubbles of the anode gas are prevented from moving to the cooling water tank 72. It is desirable that the pore size of the bubble elimination filter 74 be smaller than the diameter of the bubble of the anode gas bubbled into the water from the pipe 701.

★ Cooling Water Circulation Function By driving the pump 705 inserted in the pipe 703, the water stored in the cooling water tank 72 is supplied to the fuel cell as cooling water via the pipe 703, Water discharged from the battery returns to the cooling water tank 72 via the pipe 704 and is repeatedly used as cooling water. Since the temperature of the water returning from the pipe 704 has been raised to near the operating temperature of the fuel cell, the temperature of the water in the cooling water tank 72 is increased by the reaction heat of the battery and discharged from the battery without a heat source such as a heater. Using the cooling water as a heat medium, the temperature is raised to near the operating temperature.

★ Humidification Function Next, the humidification function of the anode gas in the humidification device 70 will be described. The anode gas is humidified by being bubbled into a water layer via a pipe 701. The humidified anode gas is supplied to the anode gas humidifying tank 7.
After staying in the space above the water layer in the fuel cell 1, it is supplied to a fuel cell (not shown) via a pipe 702. Such a flow of the anode gas is indicated by a thin arrow in FIG.

The water in the water layer of the anode gas humidifying tank 71 is exchanged with the warm water in the cooling water tank 72 through the bubble cut filter 74 (thick arrow in FIG. 10), and the water in the cooling water tank 72 is When the heat is conducted, the water becomes hot water near the operating temperature similarly to the water in the cooling water tank 72. Therefore, the humidified anode gas contains a saturated amount of water vapor at the battery operating temperature.

Also, the anode gas introduced into the water layer of the anode gas humidifying tank 71 by the bubble removing filter 74 does not enter the cooling water tank 72. The humidifier 70 as described above raises the temperature of the water by the heat generated by the battery at the time of power generation, thereby eliminating the need for a heater for heating the water and an auxiliary power unit for operating the heater. This device can simultaneously perform two different functions of humidification and cooling of the fuel cell.

★ Others In the present embodiment, the anode gas is humidified by bubbling the anode gas into the water layer. Alternatively, the anode gas may be introduced into the gas layer and the anode gas may be humidified. Ultrasonic vibrators (not shown) installed at the bottom of the gas humidifying tank 71 may generate fine water particles from the surface of the water layer, and supply an anode gas containing the fine particles to the fuel cell.

In this embodiment, only the anode gas is humidified in the humidification. However, the humidification may not necessarily be the anode gas but the cathode gas. Also,
In the present embodiment, the water in the humidifier 70 is lost due to the humidification, so it is necessary to replenish the water. However, the water generated by the oxidation reaction on the cathode side during the power generation is supplied to the manifold for discharging the cathode gas. Gas is separated from the gas discharged from the gas by a gas-liquid separator (not shown), and water is separated from the gas discharged from the manifold for discharging the anode gas by the gas-liquid separator, and the separated water is cooled. Aquarium 7
2 can also be provided.

By collecting and replenishing the water produced by the battery reaction in this way, the water lost by humidification can be replenished without separately supplying water. In the polymer electrolyte fuel cell system according to the present embodiment, a reformer (not shown) for producing a hydrogen-rich gas by performing a steam reforming reaction on a natural gas such as methane gas is provided. Gas can also be used as anode gas. In this case, it is also possible to adopt a system configuration in which the hot water in the cooling water tank is supplied with steam to a steam generator, which is turned into steam, introduced into a reformer, and used as steam for a steam reforming reaction. .

[Embodiment 3] The polymer electrolyte fuel cell system according to the present embodiment comprises a fuel cell, a humidifier 80, and a piping system for connecting them, as in Embodiment 2. The humidifier 80 humidifies both the anode gas and the cathode gas during operation. FIG. 11 is an external view of a humidifying device 80 according to the present embodiment, and FIG. 12 is a schematic sectional view.

Like the humidifying device 70 of the second embodiment, the humidifying device 80 also comprises a bottomed cylindrical tubular device main body 80a also serving as a cooling water tank for cooling the fuel cell, and a top plate 80b. The internal space 850 of the humidifier 80 is divided into two by a partition plate 83 to form an anode gas humidification tank 81 and a cathode gas humidification tank 82, and both tanks store a predetermined amount of pure water.

Further, pipes 801 to 804 for supplying and discharging the anode gas and the cathode gas are connected to the upper portion of the side surface of the main body 80a. The pipe 801 for supplying the anode gas is
The tip is inserted until it reaches the water layer in the anode gas humidification tank 81, and the anode gas discharge pipe 802 is inserted.
Is connected to a position above the water layer of the humidification tank 81.

In the same manner as above, a pipe 803 and a pipe 804 are provided in the cathode gas humidifying tank 82. In addition, a pipe 805 in which a pump for supplying cooling water to the fuel cell is inserted is connected to the bottom surface of the device main body 80a in communication with the anode gas humidification tank 81, and the cooling water from the fuel cell is connected to the top plate 80b. A pipe 806 for recovering water is connected to and connected to the cathode gas humidifying tank 82, and a pipe 807 for introducing makeup water with a control valve 817 interposed between the tank 82 and the upper side of the main body 80 a is connected. ing.

Further, a control valve 8 is provided on the lower side of the main body 80a.
The communication pipe 808 inserted therein is the cathode gas humidification tank 8.
1 and the water layer of the anode gas humidifying tank 82 are connected to each other. Also, the first pressure measurement port 8 is provided on the top plate 80b.
09 and a second pressure measurement port 810 are opened, and a pressure sensor is installed at each pressure measurement port, and the anode gas humidification tank 8 is opened.
1 and the gas pressure in the cathode gas humidifying tank 82 can be measured.

The replenishment of water lost by humidification is performed by the pipe 8
The control valve 817 inserted into the humidifier 07 is appropriately controlled by a signal from a sensor (not shown) provided in the humidifier. The control valve 818 of the communication pipe 808 is normally opened so that water in both tanks flows. However, when there is a large difference between the gas pressures in both tanks, the control valve 818 is closed and the anode is closed. The gas and the cathode gas are prevented from mixing. This control detects the gas pressure of each humidifying tank with each pressure sensor, and receives the signal to measure the pressure with each of the pressure measuring devices 841 and 842, and based on the measurement result, the anode gas humidifying tank 81 The differential pressure between the internal gas pressure and the gas pressure in the cathode gas humidifying tank 82 is processed by the differential pressure calculator 843, and the control valve is closed by the controller 844 based on the calculation result.

The anode gas is blown into the water layer of the anode gas humidifying tank 81 from the anode gas supply pipe 801, and is supplied to the fuel cell from the upper space of the tank 81 through the anode gas discharge pipe 803. It is supposed to be. Such a flow of the anode gas is indicated by a thin solid line arrow in the figure. On the other hand, the cathode gas is blown into the water layer of the cathode gas humidification tank 82 from the cathode gas supply pipe 803, and is supplied to the fuel cell from the upper space of the tank 82 through the cathode gas discharge pipe 804. It has become so. Such a flow of the cathode gas is indicated by a dotted arrow in the figure.

According to such a humidifying device 80, the same effect as that of the humidifying device 70 of the second embodiment is obtained, and both reaction gases are humidified at the same time, so that the operation of the battery can be more stably performed. . * Others The piping 805 and the piping 806 are not limited to the above-mentioned positions, and may be both provided in a cathode gas humidifying tank or an anode gas humidifying tank.

In addition, the bubble removing filter may be attached to the inside of the communication pipe 808 so that each reaction gas introduced into the water layer of each gas humidifying tank is prevented from being mixed over each gas humidifying tank. it can. [Fourth Embodiment] A polymer electrolyte fuel cell system according to the present embodiment is the same as the system of the third embodiment, except that the internal structure of the humidifier 90 is different from that of the humidifier 80.

FIG. 13 is a schematic sectional view showing the internal structure of the humidifying device 90. It is the same as the humidifier 80 in that the internal space 950 of the humidifier 90 is partitioned by a partition plate 93 to form two tanks, an anode gas humidifier tank 91 and a cathode gas humidifier tank 92. The anode gas humidifying tank 91 is divided into two first humidifying tanks 911 by a partition plate 910.
And a second humidification tank 912, and the cathode gas humidification tank 92 is divided by a partition plate 920 into two third humidification tanks 921 and a fourth humidification tank 922, and each tank stores a predetermined amount of pure water. The first and second humidification tanks are
The third humidification tank and the fourth humidification tank are communicated by a passage 910a opened at the lower end of the partition 920.

The anode gas humidifying tank 91 and the cathode gas humidifying tank 92 are connected at their lower ends by a communication pipe 930 provided with a control valve 931. This control valve 93
1 is controlled in the same manner as the control valve 818 of the third embodiment, whereby the water levels of the first to fourth humidification tanks are kept equal. The anode gas is blown into the water layer of the first humidification tank 911 from the anode gas supply pipe 901, and further blown into the water layer of the second humidification tank 912 from the upper space of the first humidification tank 911, Humidification tank 91
The fuel cell is supplied from the upper space of No. 2 to the fuel cell through the anode gas discharge pipe 903. Such a flow of the anode gas is indicated by a thin solid line arrow in the figure.

On the other hand, the cathode gas is blown into the water layer of the third humidification tank 921 from the pipe 904 for supplying the cathode gas, and further from the upper space of the third humidification tank 921 to the water layer of the fourth humidification tank 922. The fuel gas is blown and supplied from the upper space of the fourth humidification tank 912 to the fuel cell through the pipe 906 for discharging the cathode gas. Such a flow of the cathode gas is indicated by a dotted arrow in the figure.

The polymer electrolyte fuel cell system according to the present embodiment has the same effects as the system according to the third embodiment, and the humidifier 90 converts each reaction gas into water continuously with water.
Since the contact gas is humidified by being contacted twice, the humidification of the reaction gas is further advanced, and stable humidification can be performed. [Modifications] As described above, the present invention has been described based on the embodiments. However, it goes without saying that the contents of the present invention are not limited to the above-described embodiments, and the following are also included in the present invention. It is.

(A) In the first to fourth embodiments,
Although the example of the fuel cell of the internal manifold type has been described, the present invention can be similarly applied to a fuel cell of the external manifold type. (B) When operating at room temperature using the electrolyte membrane having a thickness of 20 μm in Experiment 2, the anode gas and the cathode gas are 0 ° C.
It could be operated even if it contained a water vapor amount at a dew point.

(C) Although the main material of the electrolyte membrane used in each experiment was a perfluorocarbon sulfonic acid resin, similar results were obtained when another ion exchange resin was used as the main material. Was done. (D) In the systems of the first to fourth embodiments, a heat exchanger (not shown) is installed before the cooling water reaches the fuel cell so that the temperature of the cooling water supplied to the fuel cell can be adjusted. You may. .

(E) In the humidifier of the second to fourth embodiments, when bubbling the reaction gas into the water tank, the smaller the bubbles, the more the humidification state progresses. A fine mesh filter can be provided in the portion. (F) In the humidifier of the second embodiment, the cooling water tank and the anode gas humidifying tank are each separated by a bubble filter, so that only water flows and the reaction gas is prevented from entering the tanks. If the mixing does not hinder the operation of the fuel cell, the bubble elimination filter may not be provided, and instead, a passage through which water flows may be opened at the lower end of the partition plate.

[0074]

As described above, according to the present invention, a cell in which an anode and a cathode are arranged via an electrolyte membrane and a separator plate are alternately laminated,
In a polymer electrolyte fuel cell, an anode gas channel is provided between the separator plate and the anode, and a cathode gas channel is provided between the separator plate and the cathode in close contact with the anode or the cathode, respectively.
By using a thin electrolyte membrane having a thickness of 3 μm to 40 μm, power can be generated using a reaction gas having a low dew point, and the temperature range of the humidification control can be widened to facilitate the humidification control.

On the other hand, cells in which an anode and a cathode are arranged via an electrolyte membrane and separator plates are alternately stacked, and a gas channel is formed between the separator plate and the anode and the cathode. A polymer electrolyte fuel cell provided with a water flow passage, cooling water circulating means for circulating cooling water from a water storage unit provided outside the polymer electrolyte fuel cell to the cooling water flow passage, and the water storage unit In a polymer electrolyte fuel cell system having a humidifying means for introducing and humidifying at least one of an anode gas and a cathode gas into a fuel cell, since it is not necessary to separately install a heat source for obtaining hot water or a power unit therefor, Can be simplified.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a main part of a polymer electrolyte fuel cell 1 according to a first embodiment.

FIG. 2 is a cutaway view of a main part of the polymer electrolyte fuel cell 1;

FIG. 3 is an external view of a retaining section according to the first embodiment.

FIG. 4 is a diagram showing the results of Experiment 1, showing the anode gas humidification temperature characteristics of the voltage per cell.

FIG. 5 is a diagram showing the results of Experiment 1 and showing the anode gas humidification temperature characteristics of the internal resistance value per cell.

FIG. 6 is a diagram showing the results of Experiment 2 and showing the current density characteristics of the cell voltage when both the anode gas and the cathode gas are operated without humidification.

FIG. 7 is a diagram illustrating a method of Experiment 3.

FIG. 8 is a graph showing the relationship between the thickness of an electrolyte membrane and the amount of gas cross leak as a result of Experiment 3.

FIG. 9 is an external view showing a configuration of a humidifier according to Embodiment 2.

FIG. 10 is a schematic sectional view showing a configuration of a humidifying device according to a second embodiment.

FIG. 11 is an external view of a humidifier according to Embodiment 3.

FIG. 12 is a schematic diagram illustrating an internal structure of a humidifier according to Embodiment 3.

FIG. 13 is a schematic diagram illustrating an internal structure of a humidifier according to Embodiment 4.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid polymer fuel cell 10 Cell 11 Electrolyte membrane 12 Anode 13 Cathode 20, 30 Separator plate 21 Anode gas channel 31 Cathode gas channel 40, 41 Current collector 50, 60 Sealing material 110 Cooling plate 70 Humidifier 71 Anode Gas humidification tank 72 Cooling water tank 73 Partition plate 74 Bubble cut filter 80 Humidifier 81 Anode gas humidification tank 82 Cathode gas humidification tank 83 Partition plate 808 Communication pipe 90 Humidifier 91 Anode gas humidification tank 911 First humidification tank 912 Second humidification tank 92 Cathode gas humidification tank 921 Third humidification tank 922 Fourth humidification tank 93, 910, 920 Partition plate 101 Water retention section

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01M 8/10 H01M 8/10 (72) Inventor Takahiro Isono 2-5-5 Keihanhondori, Moriguchi-shi, Osaka SANYO Electric Co., Ltd. Inside the company (72) Inventor Yo Hamada 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Yasuo Miyake 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Inside Electric Co., Ltd. (72) Masanori Kadowaki 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Shunsuke Taniguchi 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka No. Sanyo Electric Co., Ltd. (72) Inventor Toru Nakaoka 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Pref. Sanyo Electric Co., Ltd. (72) Minoru Kaneko 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric In the formula company (72) inventor depreciation tail Koji Osaka Prefecture Moriguchi Keihanhondori 2-chome No. 5 No. 5 Sanyo Electric Co., Ltd. in

Claims (7)

[Claims] 1. A solid body comprising: a cell in which an anode and a cathode are arranged via an electrolyte membrane; and a holding member for holding the cell, wherein a solid gas channel is provided between the holding member and the anode and the cathode. In a polymer fuel cell, the thickness of the electrolyte membrane is 3 to 40 μm. 2. The solid polymer fuel cell according to claim 1, further comprising humidifying means for humidifying at least one of the anode gas and the cathode gas by bringing the gas into contact with water at room temperature. Molecular fuel cell. 3. The polymer electrolyte fuel cell further includes a product water recovery unit configured to recover product water generated by a cell reaction, and an anode gas and a cathode gas using the product water recovered by the product water recovery unit. The polymer electrolyte fuel cell according to claim 1, further comprising: humidifying means for humidifying at least one of them. 4. The method for operating a polymer electrolyte fuel cell according to claim 1, wherein the operating temperature is equivalent to room temperature, and both the anode gas and the cathode gas are non-humidified. How to operate the fuel cell. 5. A cell in which an anode and a cathode are arranged via an electrolyte membrane and separator plates are alternately stacked, and a gas channel is formed between the separator plate and the anode and the cathode, and cooling is performed. A polymer electrolyte fuel cell provided with a water flow passage; cooling water circulating means for circulating cooling water from a water storage unit provided externally to the polymer electrolyte fuel cell to the cooling water flow passage; and the water storage unit Humidifying means for introducing and humidifying at least one of an anode gas and a cathode gas into the polymer electrolyte fuel cell system. 6. The polymer electrolyte fuel cell system according to claim 1,
6. The polymer electrolyte fuel cell system according to claim 5, further comprising a product water recovery unit for sending water generated by the battery reaction to the water storage unit. 7. The polymer electrolyte fuel cell system according to claim 1,
The solid according to claim 5, further comprising a reformer that generates steam using the water in the water storage unit and steam reforms the fuel gas to generate a hydrogen-rich gas. Polymer fuel cell system.